Fuel pump with automatic timer



Wfiamh 25, 1%?! A. DREasaN 2,437,915

FUEL PUMP WITH AUTOMATIC TIMER FiledLSept. 6, 1945 Patented Mar. 25, 1947 UNITED STATES PATENT 1 OFFICE International Harvester Company, a corporation of New Jersey Application September 6, 1945, Serial No. 614,787

7 Claims. 1

This invention has to do with fuel injection pumps operable to initiate injection at a time determined by the axial position of the pump cylinder, and particularly concerns apparatus for accommodating and incurring axial adjustment of the cylinder to regulate injection timing.

The general object of this invention is the provision of a simply constructedand effective timing control for fuel injection pumps.

A more specific object is the provision in a rotary cylinder pump of the piston-controlledport type of speed responsive mechanism actuated according to cylinder rotational speed for adjusting the cylinder axially and thereby regulating the time that injection commences.

Another object is the provision of an injection pump of the rotary cylinder type with a ball race constrained for rotation therewith and inertia members disposed between such ball race and a complemental ball race for exerting a component of centrifugal force between these races to vary the axial position of the cylinder and the timing of injection according to the speed of cylinder rotation.

- Another object is the provision in a rotarycylinder reciprocating plunger type fuel injection pump of a cylinder head in the form a plug telescopically associated with an end of the cylinder bore to receive the thrust endwise of the cylinder imposed on fuel charges therein, so endwise adjustment of the cylinder in controlling injection timing will be insignificantly effected by fuel compression thrusts of the plunger.

The above and other desirable objects inherent in and encompassed by the invention will be more easily understood upon reading the ensuing description with reference to the accompanying drawing, consisting of a single figure which is a vertical sectional view taken upon a plane coinciding with the axis of a fuel injection pump and timing control therefor constituting a preferred form of the invention.

A casing of the embodiment, illustrated in the drawing, is designated II. This casing has a central axial bore [2 which serves as a bearing for a cylinder l3 to facilitate both rotational and endwise movement of said cylinder. The periphery of the bearing l2 also cooperates with the cylindrical outer periphery of the cylinder l3 in providing a sealing relation between the cylinder and easing.

A central bore l4 extending centrally and axially completely through cylinder l3 contains a piston or plunger l5, which normally does not rotate but which is reciprocated endwise in the ton or plunger I5 is in its downward position,

illustrated in the drawing, all of the passages l9 will have their inner ends uncovered so that fuel from the casing passages l8 can rush into the fuel charging receiving zone II. On the ensuing upstroke of the plunger, it compresses the fuel in the zone I! upon the upper end of this plunger covering the inner ends of the passages l9, and

the fuel in the zone I'I, thereby compressed to a pressure of injection magnitude will be forced outwardly of the zone through a cylinder discharge passage 2l into one of four outlet line channels 22 with which the radially outer end 5 of said passage 2| will then be in registry. That is, the reciprocation of the plunger t5 and the rotation of the cylinder l3 are so phased that the cylinder causes the outer end of the discharge passage 2| to sweep over or be in registry with 0 successive of the circumferentially spaced delivery line channels 22 during respective upward pressure strokes of the plunger. In the embodiment herein illustrated, there are four fuel delivery channels 22, wherefore the plunger |5 is reciprocated, by means not shown, so that this plunger makes four complete reciprocations during each single revolution of the cylinder I3. Means for rotating the cylinder comprises spur gears 2'! and 28 of which the latter is formed integrally with the lower end of the cylinder. If there were a different number of fuel delivery channels 22, a correspondingly different number of reciprocations of the plunger would be had for each revolution of the cylinder. Each fuel delivery channel 22 has an upwardly turned portion leading into a recess 23 in the upper end of the casing. Each recess 23 has threaded thereinto a nipple device 24 having a check-valve asinto the combustion chambers supplied through the nipples 24. For the present disclosure, it

- will suffice to explain that the notch or cavity 29 communicates with the upper end of the plunger through an L-shaped channel 3!, so that after the upward movement of the plunger in applying injection pressure to fuel in the zone I! has progressed sufliclently for an upper metering edge 32 of the cavity 29 to arrive in registry with one of the radial channels I9, by-pass commences to take place from the zone ll through the channel 3i into said passage. Thereupon injection ceases by the termination of injection pressure. Since the metering edge 32 of the cavity 29 extends helically about the periphery of the plunger IS, the time at which this edge arrives in registry with passages 19 can be varied by controlling the rotational position of the plunger. manner the amount of fuel injected for each injection stroke of the plunger can be selectively varied.

As just explained. termination of the'injection period is incurred by the plungers metering edge 32 uncovering successive ones of the radial channels l9. Commencing of each injection period is coincident with the upper end of the plunger covering the radial passage channels 19. Conceivably, should it be desired to change the time at which the injection commences, this could be done by shifting the cylinder I3 axially so that the upper end of the plunger will completely cover and seal ofi the'inner ends of the channels l9 at a difierent time during the upward strokes of its reciprocal movement. Automatically operable timing mechanism will now be described for controlling the axial position of the cylinder.

A spring 33 surrounding the plunger at a section thereof in a gear cavity 34 of the casing ll acts expansively between the bottom of this cavity and a spring cup 35 which is slidable axially of the plunger and which is mounted upon the upper end of said spring. The upper end of the spring cup 35 serves as a ball race complementally with. an annular ball race surface 35 on the lower end of the cylinder. A plurality of ball bearings 31 disposed between the ball races 35 and 36 transmit the axial thrust of the spring 33 to the lower end of the cylinder, whereby this cylinder is yieldably urged upwardly at all times. Upward movement of the cylinder under the influence of the spring 33 is limited by a plurality of spherical rolling elements or balls 38 which react between an annular ball race 39 on the upper end of the cylinder and a complemental annular ball race ll formed on thelower end of a plug l2 screw-threaded into threaded upper end of the casing bore l2. Ball races 39 and ll are so formed that the radial elements in the peripheries of each are in diverging relation with respect to the corresponding elements of the other In this which the pump is associated for supplying fuel attains sufiicient speed (the pump being driven synchronously with such engine), this component of centrifugal force applied axially of the cylinder will reach sufficient magnitude for moving the cylinder endwise downwardly incident to compressing the spring 33. This endwise downward movement of the cylinder will cause the cylinder channels l9 to be covered by the upper end of the plunger l5 at an earlier time during upward movement of the plunger, and will correspondingly advance the time at which injection occurs. This is consonant with the desirability of the operation in internal combustion engines cf advancing the time of injection and combustion for higher engine speeds.

Proper correlation between the inertia force component generated by the balls 38 and the force exerted upwardly on the cylinder by the spring 33 with respect to the speed of the engine and the desired timing for the injection of fuel into the engine combustion chambers, can be accomplished by the selection of the mass of the balls 38, the divergence angle of the radial elements in the ball races 39 and H and the strength of the spring 33. Varying any one of these factors can be resorted to for changing the speed-timing operating characteristics of the apparatus. Their size, strength, and shape for complementally attaining the desired speed-timing characteristics is a matter of design.

What is claimed is:

. 1. In a fuel pump, a rotatable and axially displaceable cylinder having a fuel charge zone, a plunger reciprocable in said cylinder to impose pressure of fuel injection magnitude on fuel in said zone during advancing strokes of such reciprocation, means for causing the commencement of such pressure at times correlated with the axial position of the cylinder, force reaction means spaced axially from'an end of said cylinder, and inertia force developing means interposed between said force reaction means and said end of the cylinder for revolving about the cylinder axis at a speed variable in accordance with the speed of cylinder rotation, and said force developing means being operable to react between said force reaction means and said end of the cylinder to impose thereon an endwise urging force in accordance with the speed of cylinder rotation.

22. In variably timed fuel injection apparatus, a rotatable and axially displaceable pump cylinder having a fuel charge zone from which fuel is dischargeable when subjected to pressure of fuel injection magnitude, a plunger reciprocable in said cylinder to impose pressure of injection magnitude on the fuel in said zone during advancing strokes of such reciprocation, means for causing the commencement of such pressure at times correlated with the axial position of said cylinder, force reaction means having a surface in opposed spaced axial registration with an annular surface coaxial of and rotatable with said cylinder, the profiles of said surfaces being such that the radial surface elements thereof lying in opposed relation converge radially of the cylinder axis,

. rolling elements disposed reactively between said surfaces and displaceable radially of the cylinder axis, said rolling elements being revolvable about the cylinder axis at a speed variable with the rotational speed of said cylinder to develop an inertia force variable in accordance with the speed of rolling element revolution to correspondj initiation, means for controlling the axial position of said cylinder relatively vto the reciprocating range of the piston, and hence the time of injection initiation, in accordance with the rotational speed of said cylinder.

4. In a timing control for an injection pump of the piston-controlled-port type wherein the cylinder is rotated according to' the pump operating speed and wherein the position of a pistoncontrolled port of the cylinder axially of the piston is a factor in determining the time of injection initiation, bearing means wherein the rotatable cylinder is mounted for axial adjustment, an annular ball race constrained for axial movement with and coaxial with the cylinder and having a profile facing axially thereof, force reaction means having a ball race with a profile in opposed complemental relation with the first profile and also coaxial with said cylinder, the radial elements on each of said profiles converging radially outwardly in relation to the elements opposed thereto on the other profile, means yieldingly urging the cylinder in the axial direction for decreasing the space between said profiles,

'yieldingly urging means for incurring an axial position of the cylinder correlated with cylinder rotational speed..

5. In a timing control for an injection pump of the piston-controlled-port type wherein the cylinder is rotated according to the pump operating speed and wherein the position of a pistoncontrolled port of the cylinder axially of the piston is a factor in determining the time of injection initiation, bearing means in which the cylinder is mounted for rotation and for axial adjustment, an annular ball race coaxial with said cylinder and constrained for axial movement therewith, force reaction means having a ball race with a profile also coaxial with said cylinder and in opposed complemental relation with the first profile, the radial elements on each of said profiles converging radially outwardly in relation to the elements opposed thereto on the other profile, means yieldingly urging the cylinder in the axial direction for decreasing the space between said profiles, and inertia members between and rollable upon said ball race profiles while revolvedabout the axis of the rotating cylinder to develop an inertia force, and said inertia members being operable to exert an axial component .of said inertia force between said profiles to cooperate with said yieldably urging means for incurring an axial position of the cylinder correlated with cylinder rotational speed.

6. In a timing control for an injection pump of the piston-controlled-port type wherein the cylinder is rotated according to the pump operating speed and wherein the position of a pistoncontrolled port of the cylinder axially of the piston is a factor in determining the time of injection initiation, bearing means wherein the cylinder is rotatable and axially adjustable, companion gears for rotating said cylinder, one of said gears being disposed coaxially of the cylinder and being constrained for rotation therewith, the other of said gears being rotatable about an axis parallel to the cylinder axis and the teeth on said gears extending substantially parallel with their axes to facilitate axial adjustment of the I on'e'gear relatively to the other pursuant to axial adjustment of the cylinder, and means for controlling the axial position of said cylinder relatively to the reciprocating range of the piston and hence the time of injection initiation in accordance with the rotational speed of said cylinder.

7. In variably timed fuel injection apparatus, a rotatable and axially displaceable pump cylinder having a fuel charge zone from which fuel is dischargeable when subjected to pressureof fuel injection magnitude, a cylinder head having a portion projecting telescopically into the bore of said cylinder to define an end of said zone and to bear the force component of the compressed charge endwise of the cylinder so compressive force applied to said charge will not materially effect endwise displacement of said cylinder, 9. plunger reciprocable in the cylinder bore to impose pressure of injection magnitude on the fuel in said zone during advancing strokes of such reciprocation, means for causing the commencement of such pressure at times correlated with the axial position of said cylinder, bearing means in which the cylinder is mounted for rotation and for axial adjustment, an annular ball race coaxial with said cylinder and constrained for axial movement therewith, force reaction means having a ball race with a profile also coaxial with said cylinder and in opposed complemental relation with the first profile, the radial elements on each of said profiles converging radially outwardly in relation to the elements opposed thereto on the other profile, means yieldingly urging the cylinder in the axial direction for decreasing the space between said profiles and inertia members between and rollable upon said ball race profiles while revolved about the axis of the rotating cylinder to develop an inertia force, and said inertia members being operable to exert an axial component of said inertia force between said profiles to cooperate with said yieldably urging means for incurring an axial .position of the cylinder correlated with cylinder rotational speed.

ALEXANDER DREISIN..

'BEFEBENbES crrEo The following references are of record in the German 1924 

